How Long Does It Take For Rotors To Rust?

The rotors are the part of your brake system that stops your vehicle. Rotors are circular, solid pieces of metal attached to the wheel hub. Because they contain metal and frequently contact water, your rotors can rust if they are exposed to moisture. So, how long does it take for rotors to rust?

Rotors can rust within a few hours depending on protective coatings and atmospheric conditions, sometimes about a few minutes. You should know that if the rotor is made out of pure iron, iron loves oxygen and has an affinity for forming an oxide at every opportunity.

When rust occurs on rotors, it flakes off the outer layer of the iron leaving a new inner layer. This inner layer then begins to rust also until the iron begins to Pitt.

However, if rotors are treated properly with protective coatings, they can last for years. This is because protective coatings form a layer of cover over the iron and prevent oxygen from reacting with the surface of the metal.

This article answers the question “how long does it take for rotors to rust?”. It also goes further to explain the reason rotors rust and how rust affects the function of rotors. Here in this article, you’ll also understand when to change your rusty rotors and how to prevent rust on rusty rotors.

Why Do Rotors Rust When It Rains?

Rotors rust because they are made out of steel or iron. These two metals have the highest affinity for oxygen and often more than not, result in rust. Rotors are manufactured out of high carbon steel, uncoated carbon steel undergoes rust.

Why Do Rotors Rust When It Rains

The reason behind uncoating carbon steel is that the brake pads act like sanding blocks and remove all coatings including coatings formed as a result of rust. This means that whenever you drive, you sand clean the surface of the rotor, leaving behind a shining, unprotected, and bright surface.

Other metals can also be added to a rotor (metals such as chrome or nickel), to help in the formation of an alloy. These alloys are often what we refer to as stainless steel.

The downside to this however is that these alloys are not resistant to wear from the effect of braking, and your rotors will wear out as a result of abrasion instead of rust.

If you drive less and still suffer from rusty rotors, you can purchase alloys that rust less. The major issue with these alloys however is that they do not last long. Rain is not exactly what causes rotors to rust, it is a result of what it is made out of and environmental conditions.

Will Rust Affect How Your Rotors Function?

No, not exactly. Surface rust on rotors is not exactly something you should be worried about. For example, rust that appears overnight as a result of salt spray. Sometimes, metallurgy in rotors can prove to be a serious issue, but most times, a little rust on rotors will only wear brake pads a little differently, resulting in a  change of the glaze that can form where the pad brushes the rotor.

Will Rust Affect How Your Rotors Function

If this does not affect your braking, then you should not worry too much about the rust. After several brakes, much of the rust will be gone and the rust that remains will turn black as a result of the heat and interaction with the brake compound.

However, pitting rust from dirty and damp rotors that have been sitting for a long time is a big issue. This would make your braking less effective. Here, you might have to get the rotors replaced but if your rotors are thick, you might be able to peel the rust off.

Do Rusty Rotors Need Instant Replacement?

It depends on the reason they’re rusting. You need to consider a lot before thinking about replacing rusty rotors. For instance, if you drive regularly and all the brakes in your car work properly, then rusty rotors should not be an issue because the brand pads will brush any rust off of them when braking.

Do Rusty Rotors Need Instant Replacement

However, if a vehicle is driven less frequently, there could be rust on the rotors as a result of humidity. If the rotors are not completely worn out, driving slowly and braking frequently from time to time will cause the brake pads to clean any rust off the rotors. Nonetheless, there might be a risk that the rust has eaten deep into your rotors and is beginning to make the rotors pitt. In this situation, you will require a rotor replacement.

How Do You Prevent Rust On Rotors?

Rusty rotors can be prevented with proper care and maintenance. To prevent your rotors from rusting, the suitable thing to do is to keep moisture and humidity from getting to it, ideally In a garage or any indoor covered facility.

How Do You Prevent Rust On Rotors

Also, regular cleanings that will extend the working life of your rotors will do you a great good. If you work from home and hardly need your car, take it out for a slow drive at least twice a week and ensure you brake frequently.

Furthermore, a car wash is a proper way to maintain your vehicle because they clean all the dirts that get into the wrong places.

This way, your rotors are protected from the elements and are less likely to develop rust issues.

Are Rusty Rotors Noisy?

Yes, rusty rotors are noisy. A build-up of rust on your rotors will cause a squeaking or squealing noise. When exposed to moisture from rain, dew and collect on the surface of your rotors and react with oxygen. This reaction causes a layer of rust to develop on the rotor and will often squeal as long as the rust is there.

Evan Cooper

Evan Cooper

Hi, I’m Evan Cooper, the founder and an editor of this site, Doesitrust. I’m a chemical engineer and working in a rust-eliminating paint manufacturing company. Besides this profession, I’m a researcher and blogger.

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